- Distal radius fractures are not associated with a high incidence of clinically significant scapholunate diastasis
- When scapholunate diastasis is detected, the opposite wrist is likely to show a similar finding, so bilateral imaging is important
- Patients with unilateral scapholunate diastasis do not need scapholunate ligament reconstruction at initial presentation
Injury to the scapholunate interosseous ligament as part of a distal radius fracture in the wrist can have clinically important consequences. The injury can produce scapholunate dissociation that might lead to scapholunate advanced collapse of the wrist, which can cause osteoarthritis.
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It is vital to perform scapholunate ligament reconstruction before this cascade begins, but predicting which patients will develop symptoms is difficult. Acute posttraumatic radiographs often show scapholunate diastasis, but this is not always clinically relevant, as the ligament might heal during immobilization.
Neal C. Chen, MD, interim chief of the Hand & Arm Center, and Jesse B. Jupiter, MD, hand and upper extremity orthopedic surgeon of Massachusetts General Hospital and colleagues retrospectively evaluated 391 patients with distal radius fractures who were treated between 2007 and 2015 at the British Hospital of Montevideo, Uruguay. In The Open Orthopaedics Journal, they report that distal radius fractures are not associated with a high incidence of clinically important scapholunate diastasis.
All evaluated patients had undergone volar plate fixation and did not have the scapholunate joint surgically treated. The researchers measured the scapholunate interval on postoperative computed tomography. They identified 14 patients who had clinically relevant scapholunate diastasis (≥3 mm). Of these, eight (57%) also had scapholunate diastasis in the contralateral wrist.
Among the six patients with unilateral scapholunate diastasis, there were:
- 3 type C3 fractures
- 1 type C1
- 1 type B2
- 1 type A2
Two patients had an associated ulna fracture. After average follow-up of 136 weeks, five of these six patients had excellent functional outcomes, reporting a QuickDASH score of 0.
The sixth patient had a QuickDASH score of 18.2. This patient, who had bilateral degenerative osteoarthritis of both wrists before the fracture occurred, experienced more pain in the uninjured wrist at follow-up than in the injured wrist.
None of the six patients required additional surgery of the scapholunate interosseous ligament.
The researchers conclude that patients with unilateral scapholunate diastasis do not need scapholunate ligament reconstruction at initial presentation. They emphasize the importance of bilateral imaging, since more than half of the patients in this study had bilateral scapholunate intervals ≥3 mm.
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